The present invention relates generally to closure devices and, more particularly, to a slider and interlocking fastening strips. The inventive closure devices may be employed in traditional fastener areas, and is particularly well suited for fastening flexible storage containers, including plastic bags.
The use of closure devices for fastening storage containers, including plastic bags, is generally well known. Furthermore, the manufacture of closure devices made of plastic materials is generally known to those skilled in the art, as demonstrated by the numerous patents in this area.
A particularly well-known use for closure devices is in connection with flexible storage containers, such as plastic bags. In some instances, the closure device and the associated container are formed from thermoplastic materials, and the closure device and the side walls of the container are integrally formed by extrusion as a single piece. Alternatively, the closure device and side walls of the container may be formed as separate pieces and then connected by heat sealing or any other suitable connecting process. In either event, such closure devices are particularly useful in providing a closure means for retaining matter within the bag.
Conventional closure devices typically utilize mating fastening strips which are used to selectively seal the bag. With such closure devices, however, it is often difficult to determine whether the fastening strips are fully occluded. This problem is particularly acute when the strips are relatively narrow. Accordingly, when such fastening strips are employed, there exists a reasonable likelihood that the closure device is at least partially open.
Such fastening strips devices are also particularly difficult to handle by individuals with limited manual dexterity. Thus, in order to assist these individuals and for ease of use by individuals with normal dexterity, the prior art has also provided sliders for use in opening and closing the fastening strips, as disclosed, for example, in U.S. Pat. Nos. 4,199,845, 5,007,142, 5,007,143, 5,010,627, 5,020,194, 5,070,583, 5,283,932, 5,301,394, 5,426,830, 5,431,760, 5,442,838, and 5,448,808. Some of these sliders include a separator which extends at least partially between the fastening strips. When the slider is moved in the appropriate direction, the separator divides the fastening strips and opens the bag.
The closure device includes interlocking fastening strips disposed along respective edge portions of the opposing side walls, and a slider slidably disposed on the interlocking fastening strips for facilitating the occlusion and deocclusion of the fastening strips when moved towards first and second ends thereof. In accordance with the present invention, a slider is provided with a separator that drives upper ends of the fastened strips laterally apart at different controlled rates to lessen the amount of deflection and bending during deocclusion of the fastening strips.
A forward portion of the separator initially drives upper ends of the first and second fastening strips horizontally apart at about the same rate. A rearward portion of the separator then holds one of the fastening strips stationary in the horizontal axis while continuing to drive the other fastening strip horizontally outward.
The fastening strips may be one of many configurations. In one of the embodiments, the fastening strips have two sets of closure portions which form two seals between the fastening strips. The driving motion provided by the separator to the fastening strips provides for less deflection and bending in one of the sets of closure portions.
The fastening strips may include guide rails disposed between the upper and lower sets of interlocked closure portions. The guide rails slide along guide tracks provided by the housing of the slider. The guide rails also provide approximate pivot points about which the fastening strips may pivot to provide for the desired motion which facilitates easier shearing of the lower interlocked closure portions. An advantage of disposing the guide rail above the lower interlocked closure portions is that the slider may be more compact.
These and other features and advantages of the present invention will become more readily apparent upon reading the following detailed description of exemplified embodiments and upon reference to the accompanying drawings herein.